Backpack Basics

    Hydration Pack: Typically marketed as very slender sport-specific packs that cater to half- or full-day trail running, climbing, or biking outings. Often little more than a place to store your hydration pouch and a small pocket or two for snacks, money, etc. Some also come with elastic lashing cords, which could allow for a light layer. Fit is typically tight.

    Day Packs: For outings that last for six to 12 hours, sometimes more. Offers decent storage for layers, food, and water (sometimes via an internal sleeve that accommodates a hydration pouch). A lightweight waist harness and sternum straps are typical.

    Weekend Packs: Made with backpacking in mind, with ample storage inside (including space for sleeping bag, shelter, food, stove, and clothing). The hip belt is typically more burly than those in day packs. Expect ample compression straps, lash points, and other features like smaller, removable pouches, as well as sport-specific includes like loops for an ice axe or ways to carry skis or snowboards.

    Extended-Trip Packs: Like weekend packs, but with more volume to help you haul gear for multi-week excursions. Often geared toward backpacking and mountaineering.

    In an ideal world, we'd have custom-made backpacks, complete with a fit that perfectly conforms to our back, shoulders, and waist. The pack would be outfitted with the latest, lightest, most bombproof fabric. It'd have gossamer padding that reduced all hot spots on your person and made the bag feel as if it floated on air. It'd accommodate a two-week backpacking kit, or collapse to carry the barest of essentials on a quick half-day jaunt to the nearby park. And then all we could complain about is running out of silver polish for our diamond tiaras. Until then, finding the right pack for your price range and interest is essential to enjoying the outdoors; the wrong pack can result in a sore back and shoulders, bruised hips, and a sometimes dangerous loss of balance. But the right one makes everything all right.

    As with most gear, scoring the right item comes down to understanding the needs of your specific your adventures. Volume, shape, weight, internal compartments, external pockets, materials, and harness type and size all play a role. But to keep things simple, we break it down to the following five essentials:

    1. Your Needs 
    These days backpacks are more specialized than ever. One backpack won't work for everything, so if you're buying a new pack, spend some time thinking about your ideal end use. Do you need a day pack that doubles as a computer bag, or will it be solely a weekend warrior resource? Or do you want something that can transition from a day hiker to an ultralight overnight or long weekend? Or maybe you need a kit that'll match multi-day or even multi-week backpack ambitions? Knowing how you plan on using the pack removes a lot of guesswork. A pack that's built specific to trail running or biking, for example, fulfills different needs than one for day hiking, commuting, or traveling.

    Tip: Personal preference also comes into play: Are you a fan of the hydration bladders, or do you prefer to slip your water into the side pockets? Do you enjoy little bells and whistles like a key clip on an inside pocket and loads of organizational options, or do you embrace the ultralight philosophy that might lead you to cut off the pack labels to save a gram. Know you're going to hike mostly in temperate weather and thus don't need something that can carry three extra layers? Considering questions like these will make finding the right pack even easier.

    2. Volume 
    Most packs are sized in cubic inches or liters. For example, 2,400 cubic inches of volume, which translates to just under 40 liters, is the average size of a day pack. Go any lower in volume and you're looking at a book bag or hydration pack. For bigger loads (two to three travel days, or climbing with a “trad” rack), consider 2,500- to 3,500-cubic-inch packs. Packs above 3,500 cubic inches (nearly 60 liters of load-carrying capacity) are ideal for weekend-long backpacking trips when you need food, shelter, sleeping bag, and pad. The really big haulers, with 4,000 cubic inches or more of load-carrying capacity (65 plus liters), are ideal for serious mountaineering or backpacking trips when you are packing 40 to 50 pounds of supplies.

    Tip: Manufacturers' estimates of pack volume is not an exact science. When shopping for a new pack, try stuffing it with whatever product you plan on toting around—sleeping bag, tent, stove, hydration system, skis, snowboard, etc. If you want to be REALLY precise, you can always double check volume by filling the pack with pre-measured peas or rice. Also, don't forget to factor in carrying methods beyond the actual bag volume itself; lash points and compression straps allow you to tie on sleeping pads, cooking gear, and extra layers without swallowing some of that precious internal space.

    3. Fit 
    Fit is based on torso length, which is the distance from the top of your shoulders to the top of your hips (sometimes referred to as the iliac crest). Many packs have a torso length adjustment, or come in multiple sizes, or both. Others have a variety of shoulder-strap and hip-belt configurations that can be tailored to your particular form. Some manufacturers, such as Osprey, even let you custom-mold your hip belt (thanks to an in-store heating process), while others offer a bit of DIY customization, provided you have an oven at home. In general, you want a pack's hip belt to hit at the hips when synced tightly, with your shoulder straps positioned so that you can stand comfortably upright—the heavier the load, the more important this is.

    Back ventilation is also something that has made strides in the last few years, with some designs employing what looks like a trampoline between you and the actual pack. It allows for greater breathability—heaven on humid days—but could prove fragile when you use it as checked luggage.

    For day packs, those with a narrower, more streamlined fit (read: ones that are a touch more vertical than square) allow freer arm movement, a nice detail for bouldering, trail running, and mountain biking.

    Tip: Regardless of your pack's size and shape, the balance point of the load is critical. The load should ride securely as close to your back as possible. The harness should hold the pack snugly, with no wiggling as you move. Many packs are “expandable” via straps to accommodate additional gear. However, the best packs expand up (with a floating lid), rather than out.

    4. Weight and Materials 
    Check the pack's weight before you buy. Ultralight packs shave off pounds by using smaller buckles, ultralight materials, and thin straps. The downside is less durability and comfort over the long haul. Conversely, excessive padding, straps, and pockets result in too much weight. The sweet spot is the right mix of comfort and durability. In general, consider packs with lighter fabric that is still durable. Shoulder straps and hip belt should be thick enough to be comfortable and substantial enough to not break down over time.

    Tip: Most packs are water-resistant; the many seams and zippers in packs make it hard to award packs with the seal of total waterproofness. If you plan on hiking during a deluge, you can buy inexpensive rain covers from stores like REI and EMS. Or just get a small dry bag to go inside your pack—an essential should you be hauling costly electronics. Heavy-duty trash bags also work well as a waterproof inner lining.

    5. Compartments and Lash Points 
    Most packs (big and small) load from the top—it's just the easiest way to compress a bag's contents. But some have separate side or front zippers to help access certain gear like a sleeping bag or hydration system, a feature that makes life easier in the backcountry. However, if you're looking for something to use as a travel pack, avoid top-loaders, or you'll have to dump out everything whenever you need to find that one thing that always migrates to the bottom of the pack. Ideally a pack will have strategically placed zippers and pouches without losing its streamline shape. If you are planning on using the pack for mountaineering, skiing, or riding, check the exterior lash points to make sure they work with your hardware.

    Tip: We love packs (big and small) that come with a key clip as well as little zipper pouches on the waist belt that can fit a point-and-click camera or cell phone. Commuters and in-flight day-trippers should consider packs with padded laptop sleeves. Weekend and long-haul packs with detachable (or “floating”) upper pockets also give you the option to ditch the big pack for a quick jaunt to an overlook, or to keep food or electronics within easy reach.